HEISLER Decoder fitting query

[Stevelewis]

Hi
I have  recently  fitted  and  ESU Loksound XL  decoder in a Heisler  and  it  operates  succesfully,  However  I was  wondering  what  the  purpose  of  the  2  red  and  2 black  cables are  which  are not  connected to anything but    as  delivered  were  simply  wrapped  in  Sellotape to insulated  the  ends?

I suspect  they  may be connected  with  sound  synchronisation?
regards  Steve  Lewis
MOLD  North  Wales  UK